Characterising transport in a quantum gas by measuring Drude weights

Abstract

Transport properties play a crucial role in defining materials as insulators, metals, or superconductors. A fundamental parameter in this regard is the Drude weight, which quantify the ballistic transport of charge carriers. In this work, we measure the Drude weights of an ultracold gas of interacting bosonic atoms confined to one dimension, characterising the induced atomic and energy currents in response to perturbations with an external potential. We induce currents through two distinct experimental protocols; by applying a constant force to the gas, and by joining two subsystems prepared in different equilibrium states. By virtue of integrability, dynamics of the system is governed by ballistically propagating, long-lived quasi-particle excitations, whereby Drude weights almost fully characterise large-scale transport. Indeed, our results align with predictions from a recently developed hydrodynamic theory, demonstrating almost fully dissipationless transport, even at finite temperatures and interactions. These findings not only provide experimental validation of the hydrodynamic predictions but also offer methodologies applicable to various condensed matter systems, facilitating further studies on the transport properties of strongly correlated quantum matter.

10 pages, 6 figures. Comments are welcome

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Cited by in corpus (4)

• Experimental Investigation of a Bipartite Quench in a 1D Bose gas
• Ballistic particle transport and Drude weight in gases
• Exotic critical states as fractional Fermi seas in the one-dimensional Bose gas
• Quantum transport in 1D Hubbard model: Drude weights and Seebeck effect